"Three compliant bids have been received.They will be evaluated over the next few months with a view to making an award around the end of the year," a spokesman said.

The spokesman said the Shah Deniz consortium, which also includes Norway's Statoil and Azeri state-controlled Socar, is also still considering a fourth option, of building its own pipeline through south-east Europe.

Sources close the consortium have said that it has doubts about the abilities of each of the three bidders to make credible partners.